GPS-based positioning system for mobile GPS terminals

ABSTRACT

The present invention discloses a GPS system that uses call-processor intelligence to determine the mode of operation of a GPS receiver located in a GPS terminal. The modes are selected based on the availability of network facilities, the GPS information that can be acquired, or user input requirements.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates in general to Global Positioning System(GPS) mobile terminals, and in particular to a call processing (CP)centric architecture for mobile GPS terminals.

2. Description of the Related Art

Cellular telephony, and the associated features of cellular telephony,have become a part of everyday life around the world. The use ofcellular telephone devices to provide voice, data, and other services,such as internet access, has provided many conveniences to cellularsystem users.

A current thrust in the cellular arena is the integration of GlobalPositioning System (GPS) technology into cellular telephone devices andother wireless transceivers. The use of GPS information in the cellulartelephone (cell phone) can be used by the user for navigation, locationservices, or for reporting the position of the phone to an outsideagency such as emergency services, police, or a friend, for ease oflocating the cellular user.

Further, GPS data that is supplied to the mobile telephone can be usedby the mobile telephone user for directions, latitude and longitudepositions (locations or positions) of other locations or other mobiletelephones that the cellular user is trying to locate, determination ofrelative location of the cellular user to other landmarks, directionsfor the cellular user via internet maps or other GPS mapping techniques,etc.

Cell phones can be used in many environments, e.g., outside, indoors, inurban environments, or in rural areas. As such, there are manysituations where a cell phone that has an integrated GPS receiver cannotreceive GPS signals, because the cell phone is blocked from receivingsuch signals. Urban canyons, heavy foliage, or other scattering orblocking structures will prevent the receiver from getting theinformation it needs to determine the location of the cell phone. Thecellular system can then be used to deliver information to the GPSreceiver for the GPS receiver to perform the necessary calculations,however, the decision of what information is needed is currentlyresident outside of the call processing processor.

It can be seen that there is a need in the art for GPS enabled cellulartelephones. It can also be seen that there is a need in the art fordecision making intelligence within the call processing processor.

SUMMARY OF THE INVENTION

To minimize the limitations in the prior art described above and tominimize other limitations that will become apparent upon reading andunderstanding the present specification, the present invention disclosesa system determining the position of a GPS terminal. The systemcomprises a GPS terminal and a location aiding server. The GPS terminalincludes a GPS section for receiving and processing a GPS signal, astrategy selector, external to and coupled to the GPS section, thatdetermines a positioning strategy based upon a state of the GPS section,and a communication system, coupled to the GPS section and the strategyselector, for transmitting and receiving data to and from the locationaiding server. The location aiding server communicates with thecommunications system of the GPS terminal via a communications network,and includes an aiding data generation section for forming locationaiding data and a communication control section for transmitting data toand receiving data from the GPS terminal.

An object of the present invention is to provide for GPS enabledcellular telephones. Another object of the present invention is toprovide a system that has decision making intelligence within the callprocessing processor.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the drawings in which like reference numbers representcorresponding parts throughout:

FIG. 1 illustrates a typical GPS architecture as used in a cellularenvironment;

FIG. 2 shows a typical interface between the Call Processing section andthe GPS section of the present invention;

FIG. 3 illustrates details of a GPS terminal of the present invention;

FIG. 4 illustrates a server in accordance with the present invention;and

FIGS. 5 and 6 are flowcharts illustrating the steps used to practice thepresent invention.

DETAILED DESCRIPTION OF THE DRAWINGS

In the following description of the preferred embodiment, reference ismade to the accompanying drawings which form a part hereof, and in whichis shown by way of illustration a specific embodiment in which theinvention may be practiced. It is to be understood that otherembodiments may be utilized and structural changes may be made withoutdeparting from the scope of the present invention.

Overview

When integrating GPS components with wireless communications systems,the GPS system must have the capability to acquire and track the GPSsatellites under the conditions that the typical wireless communicationssystem user will encounter. Some of those conditions, e.g., indoor use,dense urban areas use that has a limited sky view, such as in downtownareas with skyscrapers blocking satellite views, etc., are possible withterrestrial-based wireless communications systems but present difficultsituations for GPS systems. Traditional standalone mode GPS, e.g., wherethe GPS receiver does not receive any outside assistance, has problemswith long Time To First Fix (TTFF) times, and also has limited abilityto acquire the GPS satellite signals under indoor or limited sky-viewconditions. Even with some additional information, TTFF times can beover thirty seconds because ephemeris data must be acquired from the GPSsystem itself, and also requires a strong signal to acquire suchinformation reliably. These requirements of the GPS system have impactson the reliability of position availability as well as power consumptionin handheld GPS terminals.

Overview of the Present Invention

In the present invention, a server-client (or server-terminal)architecture is used. The terminal-side user has a GPS terminal, such asa cellular phone, and directly accesses to the terminal via a userinterface section of the terminal. The server-side user can access theserver via a user interface section of the server or from a userterminal via a network. Accordingly, a positioning request from a userneeds to be received at both the terminal and the server. Furthermore,notice of a positioning result to a user needs to be made to both theterminal-side user and the server-side user.

GPS Architecture

FIG. 1 illustrates a typical GPS architecture as used in a cellularenvironment.

The wireless handset location technology of the present invention usesGPS technology in support of various wireless handset devices for theimplementation of E911 and geo-location services. By taking theadvantage of the low cost, low power, high performance and high accuracyGPS receivers enabled by the present invention, as well as the wirelessnetwork communication services, the wireless handset location technologyof the present invention provides highly reliable and economicalsolutions to the Wireless Aided GPS.

The wireless handset location technology of the present inventionsupports all kinds of geo-location services, from fully standalone mode,network aided mode, to network based service mode, to other modes. Thetechnology of the present invention also accommodates wide range ofwireless communication platforms, including CDMA, TDMA, AMP, and evenpager systems. FIG. 1 portrays the concept of wireless handset locationtechnology.

System 100 illustrates a GPS satellite 102, which is illustrative of theconstellation of GPS satellites 102 that are in orbit, a wireless GPSterminal 104 that comprises a GPS receiver, a base station 106, ageo-location (server) service center 108, a geo-location end application110, and a Public Safety Answering Point (PSAP) 112.

The GPS satellite 102 transmits spread spectrum signals 114 that arereceived at the wireless GPS terminal 104 and the geo-location server108. For ease of illustrative purposes, the other GPS satellites 102 arenot shown, however, other GPS satellites 102 also are transmittingsignals 114 that are received by the wireless GPS terminal 104 and thegeo-location server 108. If the wireless GPS terminal 104 can receive astrong enough signals 114, the GPS receiver in the wireless GPS terminal104 can compute the position of the wireless GPS terminal 104 as istypically done in the GPS system. However, wireless GPS terminals aretypically not able to receive strong enough signals 114, or are not ableto receive signals from enough GPS satellites 102 to autonomouslycompute the position of the wireless GPS terminal 104, but can stillcommunicate with the base station 106. Thus, the base station 106 cancommunicate information via signals 116 to the GPS terminal 104 to allowthe GPS terminal 104 to compute the location. If the basestation 106 istransferring information to the GPS terminal 104 to allow the GPSterminal 104 to compute position, it is called “wireless-aided GPS”.Furthermore, the basestation 106 can communicate aiding data from thegeolocation server 108 to the GPS terminal 104 to allow the GPS terminal104 to compute its position, or can communicate information from the GPSterminal 104 to the geo-location server 108 to allow the geo-locationserver 108 to compute the position of the GPS terminal 104. When thebasestation 106 transfers information from the geolocation server 108 tothe GPS terminal 104 it is called “network aiding GPS”, whereas when thebasestation 106 transfers information from the GPS terminal 104 to thegeo-location server 108 for the geo-location server 108 to compute theposition of the GPS terminal 104 it is called “network-centric GPS.”

The geolocation server 108 also communicates with the geolocation endapplication 110 via signals 118 and with PSAP 112 via signals 120. Thesesignals 118 and 120 can either be via wireless links or can be throughthe land line telephone network or other wire-based networks.

The wireless GPS terminal 104 location technology of the presentinvention comprises two major service systems: the wireless GPS terminal104 with the GPS receiver of the present invention and the geo-locationserver 108 containing the geo-location software modules of the presentinvention. In addition, there are two types of supporting systems: theBase Station (BS) 106 infrastructure, which provides the networkinformation transfer mechanism, and the PSAP 112 or the application 110system, which can initiate the geo-location network services.

FIG. 2 shows a typical interface between a Call Processing section andthe GPS section of the present invention.

As shown in FIG. 2, the GPS terminal 104 comprises a Call Processing(CP) section 200 and a Global Positioning System (GPS) section 202.Within the GPS terminal 104, or, alternatively, between the GPS terminal104 and an external accessory to the GPS terminal 104, communicationsbetween the CP section 200 and the GPS section 202 take place. Thesecommunications allow signals to be transferred from CP section 200 toGPS section 202, and typically take place on a serial communicationslink 204 and hardware lines 206, but other connections can be used ifdesired.

For example, in another implementation, the CP section 200 and the GPSsection 202 can share the same digital processor and other circuitry. Insuch a case, the communication between sections can be made byinter-task communication, and certain data transfers, such as any timeor frequency transfers between the CP section 200 and the GPS section202, would not use the hardware lines 206, but would be internal to thecircuitry or, potentially, no transfer would be required depending onthe circuit design.

GPS Terminal

FIG. 3 illustrates details of the GPS terminal 104 of the presentinvention.

GPS CP-centric terminal 104 (300) can receive user-generated positioningrequests 302 and display positioning results 304 via a user interface306. In turn, user interface 306 generates positioning request 308 whichis used by a processing section 310 in determining which variables mustbe set, etc. to determine the position of the GPS terminal 300.

Included in the positioning request 308 are positioning requirements,e.g., position accuracy, positioning time, positioning cost, etc., and adestination notification, e.g., to which side of the user the positionresults should be sent, the GPS terminal side, or the geo-locationserver side. The information about destination is stored in theprocessing section 310 of the GPS terminal 104 and is used to notify theuser of the route and the result of the location determination (thepositioning result). The positioning requirements are then transmittedto the mode determinator 312 and to the aiding data determinator 314.

The mode determinator 312 and the aiding data determinator 314 interfacewith the GPS section 202. The mode determinator 312 sends information316 to the GPS section 202, e.g., positioning requirements, etc. The GPSsection 202 then sends state information 318 of the GPS section 202 tothe mode determinator 312.

The aiding data determinator 314 receives request 320 from the GPSsection 202 which asks the aiding data determinator 314 for assistancein acquisition or tracking of GPS signals being performed by the GPSsection 202. The aiding data determinator 314 returns aiding data 321 tothe GPS section 202.

GPS Terminal Operation

Typically, a user will access the GPS terminal 104 via the userinterface 306. The user will make a position request 302, which request308 is passed to the processing section 310. The destinationnotification included in the position request is stored in processingsection 310. The processing section 310 determines what mode the GPSsection 202 will use via the mode determinator 312. The GPS section 202either provides without query, or, upon query, a predicted accuracy andTTFF to the mode determinator 312 and the aiding data determinator 314.

The mode determinator 312 uses another input, a network communicationstate input 322, to determine which state the GPS section 202 will beoperated in. If the network is not available, then the GPS section 202operates in Stand Alone Mode. Otherwise, depending on the state result318 of the GPS section 202, the GPS section 202 can be operated in othermodes.

If the network communication state input 322 indicates that the networkis available, the aiding data determinator 314 can ask the server 108via the network connection 324 for an approximate position request. Ifsuch an approximate position is available, the server 108 will providethe approximate position 326 to the aiding data determinator 314, whichtransfers the aide 321 to the GPS section 202.

If the GPS terminal 104 position has been requested by the server 108,positioning request 328 is sent via the network from the server 108 tothe processing section 310. The processing section 310 can also report apositioning result 330 to the server 108, as well as share a positioningresult 332 with the server 108.

When a position result 334 (a location calculation) is determined by theGPS terminal 104, such information and destination notification istransmitted to the processing section of the server 108 via link 332when the GPS terminal 104, specifically the mode determinator 312portion of the call processor, selects a network-centric mode in whichthe server 108 will do final calculation such as differentialcorrection. After the final calculation, the server 108 reports theposition to the user of the server or sends back it to the GPS terminal104 based on the destination notification. If the GPS section 202 of theGPS terminal 104 determines the location of the GPS terminal 104, it didnot need further assistance, and therefore, information does not need tobe transmitted to the server 108 for assistance. Finally, the positionresult 336 is forwarded from the processing section 310 to the userinterface 306 for display 304 to the user if the destinationnotification indicates the position should be delivered to GPS terminaluser. On the other hand, the final position result 336 is sent to thegeolocation server 108 based on the destination notification.

Mode Determinator

The mode determinator 312 selects an optimum positioning mode based onthe positioning request 302, the state 318 of the GPS section 202, andthe state of the network 322. Several positioning modes, such as StandAlone mode, Network Aiding mode and Server Centric mode are available tothe mode determinator 312.

Stand Alone mode is a mode for performing positioning by only aterminal. Network Aiding mode is a mode for performing positioning by aterminal with being aided by a server. Server Centric Mode is a mode forperforming positioning by a server.

The mode determinator 312 first acquires the positioning requirementsvia request 302. These requirements can be designated by the positioningrequest 302 and can be stored in the GPS terminal 104 in advance. Alsothe positioning requirements may be acquired by inquiring via the userinterface section 306 of the GPS terminal 104 during positioningprocessing. The positioning requirements include a positioning accuracyrequest, a positioning sensitivity request, a positioning time requestand a positioning cost request.

The mode determinator 312 selects Stand Alone mode when the modedeterminator 312 determines, from the positioning cost request and thecommunication state 322 of the network, that the modes using a networkare disabled. The modes using a network are Network Aiding mode, andServer Centric mode. The mode determinator 312 also selects Stand Alonemode when the cost exceeds the positioning cost request by the user, orin the case where it is impossible to use the network.

Next, the mode determinator 312 checks the positioning accuracy request,and where the accuracy request exceeds a possible level in the GPSterminal 104 positioning, the Sever Centric mode, which enablespositioning operation with higher accuracy, is selected. Furthermore,when communication delay of the communication state of the networkexceeds the upper limit that can ensure necessary accuracy in thepositioning modes using a network, Stand Alone mode is selected.

Next, the mode determinator 312 determines whether aiding by the server108 is necessary based on the positioning sensitivity request and thepositioning states of the GPS section 202. In the case where the signallevel of the satellites being acquired is lower than or equal to thelower limit that the terminal can acquire Ephemeris and time, and thepositioning sensitivity request requests for the sensitivity that can bepositioned by signals of the level lower than or equal to this level,aiding from the server 108 becomes essential for positioning, so thatNetwork Aiding mode is selected.

The mode determinator 312 carries out prediction calculation ofpositioning time for each mode, and compares the result with thepositioning time request of the positioning requirements. For predictionof the positioning time, positioning states 318 of the GPS section 202are used. Positioning states 312 of the GPS section 202 includepresence/absence of correct time and Ephemeris necessary forpositioning, a current step of the GPS section in the satelliteacquiring processing and positioning operation, the number of acquiredsatellites and a signal level of the acquired satellites as acquiringstates of satellites are used. For prediction of the positioning time,besides the positioning states 318, the communication state 322 of thenetwork and the positioning sensitivity request of the positioningrequirements of the positioning request 302 are used.

When the predicted positioning time is shorter than the positioning timerequest, the mode determinator 312 gives a priority on the positioningcost and selects Stand Alone mode. In the case where the predictedpositioning time is longer than the positioning time request, the modefor minimizing the positioning time is selected.

Aiding Data Determinator

The aiding data determinator 314 processes approximate position data 326from the server 108, and determines what, if any, aiding data that theGPS section 202 needs. The terminal approximate position 326 is used forincreasing the speed of acquiring a signal from a GPS satellite 102 bythe GPS section 202.

The aiding data determinator 314 first acquires positioning requirementsdesignated by the user when a position request 302 is made. Theserequirements can be designated by the positioning request 302 and can bestored in the GPS terminal 104 in advance. Furthermore, the positioningrequirements may be acquired by inquiring the user via the userinterface 306 of the GPS terminal 104 during positioning processing.

The aiding data determinator 314 performs a prediction calculation ofpositioning time both with and without the approximate position data326. These results are compared with the positioning time request andthe positioning requirements in request 302. The aiding datadeterminator 314 also uses positioning state 320 of the GPS section 202to predict the positioning time. A positioning state 320 of the GPSsection 202 can be one or more of the following: elapsed time since thelast position; presence or absence of a position calculation within apredetermined time period; the current processing step in a satelliteacquiring processing sequence in the GPS section 202; the number ofacquired satellites; and a signal level of the acquired satellites.

When the predicted positioning time is shorter than the positioning timerequest, the aiding data determinator 314 waits for the GPS section 202to carry out positioning while checking the positioning state 320 of theGPS section 202 without acquiring approximate position data 326. Ifthere is a change in the positioning state 320 of the GPS section 202,the flow returns to the prediction calculation processing of positioningtime. If the GPS section 202 completes the position calculation beforean approximate position is determined, acquisition of the approximateposition data 326 is skipped.

When the predicted positioning time is longer than the positioning timerequest, then the positioning time and the cost, e.g., the amount oftime it will take at a certain cost per unit time of using the network,the cost for information being sent by the network, etc., at the time ofacquiring an approximate position are calculated. To properly determinethe cost, states such as the communication speed of the network used foracquiring an approximate position, communication cost, and cost of theapproximate position acquiring service are used. Depending on thepredicted calculation time, the cost of acquiring an approximateposition, and the required postioning time, an approximate position canbe acquired from the server 108.

When the positioning time does not become shorter even if an approximateposition is acquired, or in the case where the required cost exceeds thepositioning cost request, a approximate position is not acquired.Furthermore, in the case where it is impossible to connect to theserver, an approximate position is not acquired and the device proceedswith satellite acquiring processing.

Server Operation

FIG. 4 illustrates a server 108 in accordance with the presentinvention.

System 400 illustrates the server 108, having a user interface 402, aprocessing section 404, operation section 406, and aiding data creator408.

The user interface 402 can receive a position request 410 from theserver 108 user, and deliver a positioning result 412 to the user. Userinterface also sends the position request 414 to the processing section404, and receives results 416 from the processing section 404.

The processing section 404 sends server calculated results 328 to theGPS terminal 300, receives terminal-calculated results 330 from the GPSterminal 300, and shares results and destination notification 332 withprocessing section 310 of the GPS terminal 300. The processing section404 also receives positioning results from operation section 406.

The operation section 406 receives aiding data 418 from a aiding datacreator 408, and either uses that data 418 to determine a positionresult 420 to report to the processing section 404, or sends the aidingdata 326 to the GPS terminal 104, either in response to a request 324 orautomatically.

Server Operation

The user interface 402 enables the user to directly input a positioningrequest to the server 108 and to input a positioning request from theuser terminal via a network. Included in the positioning request 410 arepositioning requirements, e.g. positioning accuracy, positioning time,positioning cost, etc. and a destination notification. The processingsection 404 of the server 108 transmits the inputted positioning request328 to the processing section 310 of the GPS terminal 104. Furthermore,the notifying destination information included in the positioningrequest is stored in the processing section 404 of the server 108 foruse in notification of a positioning result and it is also sent to theGPS terminal 104 via link 332. A positioning result is obtained eitherin the GPS section 202 of the GPS terminal 104 or in the operationsection 406 of the server 108 depending on the positioning mode selectedby the mode determinator 310.

When the positioning result is obtained in the GPS section 202 of theGPS terminal 104, the GPS section 202 transmits the positioning result334 to the processing section 310 of the GPS terminal 104. Theprocessing section 310 of the GPS terminal 104 informs the user of thepositioning result 304 via the user interface 306 of the GPS terminal104, or transmits the positioning result 330 to the processing section404 of the server 108 on the basis of the stored notifying destinationinformation. The positioning result 330 transmitted to the processingsection 404 of the server 108 is given to the server 108 user via theuser interface 402 on the basis of the stored notifying destinationinformation.

When the positioning result is obtained in the operation section 406 ofthe server 108, the operation section 406 transmits the positioningresult to the processing section 404 of the server 108. The processingsection 404 of the server 108 directly sends the positioning result tothe user via the user interface 402 of the server 108 or transmits thepositioning result 328 to the processing section 310 of the GPS terminal104 on the basis of the stored notifying destination information.

Process Charts

FIGS. 5 and 6 are flowcharts illustrating the steps used to practice thepresent invention.

Block 500 illustrates starting the approximate position acquisitionprocess.

Block 502 illustrates acquiring the positioning time request in the userpositioning requirement. Block 504 illustrates predicting thepositioning time without getting an approximate position.

Block 506 is a decision block that determines whether the predictedpositioning time is shorter than the positioning time requested by theuser. If the predicted positioning time is shorter than the requestedtime, control passes to block 508; if not, control passes to block 510.

Block 508 is a decision block that determines if the positioningcalculation is completed. If so, control passes to block 512; otherwise,control passes to block 514.

Block 514 is a decision block that determines if the GPS state haschanged. If so, control passes back to the input to block 504;otherwise, control returns to the input to block 508.

Block 510 determines the time and cost for getting an approximateposition.

Block 516 is a decision block that determines if the calculated time andcost for acquiring an approximate position meet the user request. If so,control passes to block 518; otherwise, control passes to block 512.

Block 518 is a decision block that determines if there is an availableconnection to the server. If so, control passes to block 520, where anapproximate position is acquired from the server, and control thenpasses to block 520. Otherwise, control passes to block 512, which endsthe approximate position acquisition process.

FIG. 6 starts with block 600, the beginning of the positioning modedetermination process. Block 602 illustrates acquiring the positioningtime request from the user positioning requirement. Block 604 is adecision block that determines if the network is available given thenetwork status and the cost of using the network. If the network isdetermined to be available, control passes to block 606, otherwise,block 608 is selected, where the stand-alone mode is selected.

Block 606 is a decision block that determines if the user requestedaccuracy is available at the GPS terminal. If so, control passes toblock 610; if not, control passes to block 612, where the server centricmode is selected.

Block 610 is a decision block that determines if the network latency forobtaining the user requested accuracy is acceptable. If so, controlpasses to block 614; if not, control passes to block 608, where thestand-alone mode is selected.

Block 614 is a decision block that determines if the signal level andsensitivity required for stand-alone mode are available. If not, controlpasses to block 616, where the server aiding mode is selected. If so,control passes to block 618, where the positioning time for each mode isdetermined.

Block 620 is a decision block that determines whether there is enoughavailable time for the user requirement in stand-alone mode. If so, thestand-alone mode is selected in block 608; otherwise, block 620 is usedto select the mode that minimizes the positioning time.

CONCLUSION

This concludes the description of the preferred embodiment of theinvention. The following paragraphs describe some alternative methods ofaccomplishing the same objects. The present invention, althoughdescribed with respect to GPS systems, can be utilized with anySatellite Positioning System (SATPS) without departing from the scope ofthe present invention.

In summary, the present invention discloses a system determining theposition of a GPS terminal. The system comprises a GPS terminal and alocation aiding server. The GPS terminal includes a GPS section forreceiving and processing a GPS signal, a strategy selector, external toand coupled to the GPS section, that determines a positioning strategybased upon a state of the GPS section, and a communication system,coupled to the GPS section and the strategy selector, for transmittingand receiving data to and from the location aiding server. The locationaiding server communicates with the communications system of the GPSterminal via a communications network, and includes an aiding datageneration section for forming location aiding data and a communicationcontrol section for transmitting data to and receiving data from the GPSterminal.

The foregoing description of the preferred embodiment of the inventionhas been presented for the purposes of illustration and description. Itis not intended to be exhaustive or to limit the invention to theprecise form disclosed. Many modifications and variations are possiblein light of the above teaching. It is intended that the scope of theinvention not be limited by this detailed description, but rather by theclaims appended hereto.

1. A Global Positioning System (GPS)-based positioning systemcomprising: (a) a GPS terminal, including: (i) a GPS section forreceiving and processing a GPS signal; (ii) a strategy selector,external to and coupled to the GPS section, that determines apositioning strategy based upon a state of the GPS section; and (iii) acommunication system, coupled to the GPS section and the strategyselector, for transmitting and receiving data to and from a locationaiding server, and (b) a location aiding server, which communicates withthe communications system of the GPS terminal via a communicationsnetwork, including: (i) an aiding data generation section for forminglocation aiding data; and (ii) a communication control section fortransmitting data to and receiving data from the GPS terminal.
 2. Thesystem of claim 1, wherein the location aiding server calculates aposition of the GPS terminal based upon data received from the GPSterminal.
 3. The system of claim 1, wherein the strategy selectorcomprises a mode determinator for determining a mode of operation of theGPS section based upon the state of the GPS section.
 4. The system ofclaim 3, wherein the state of the GPS section is determined by at leastone parameter selected from a group comprising: a signal level ofreceived satellite signals, a number of satellites from which signalsare being received, a frequency range used for searching for satellites,a time range used for searching for satellites, a current searchingstatus, and a state in a positioning process sequence.
 5. The system ofclaim 3, further comprising a time estimator for computing an estimatedpositioning time based upon the state of the GPS section, wherein themode determinator determines the mode of operation of the GPS sectionbased upon computed estimated positioning time.
 6. The system of claim3, wherein the mode determinator determines the mode of operation byusing at least one parameter selected from a group comprising: acommunication state of the communications network between the GPSterminal and the location aiding server, a communications cost, and auser request, wherein the user request is at least one request selectedfrom a group comprising: positioning accuracy, positioning time,positioning costs, and positioning sensitivity.
 7. The system of claim6, wherein the communication state is determined by at least oneparameter selected from a group comprising: an availability of acommunication link to the location aiding server, an effective datatransmission rate between the GPS terminal and the location aidingserver, and a communication delay characteristic between the GPSterminal and the location aiding server.
 8. The system of claim 3,wherein the GPS terminal further comprises a terminal destinationcalculator for selecting a destination of a terminal calculated positionof the GPS terminal and for sending the position, and wherein thelocation aiding server further comprises a server destination calculatorfor selecting a destination of a server calculated position of the GPSterminal and for sending a server calculated position of the GPSterminal.
 9. The system of claim 8, wherein the destination of thecalculated position of the GPS terminal is shared between the GPSterminal and the location aiding server.
 10. The system of claim 1,wherein the strategy selector comprises an aiding data determinator fordetermining a method for acquiring position aiding data based upon thestate of the GPS section.
 11. The system of claim 10, wherein the stateof the GPS section is determined by at least one parameter selected froma group comprising a signal level of received satellite signals, anumber of satellites from which signals are being received, a frequencyrange used for searching for satellites, a time range used for searchingfor satellites, a current searching status, and a state in a positioningprocess sequence.
 12. The system of claim 10, further comprising a timeestimator for computing an estimated positioning time based upon thestate of the GPS section, wherein the aiding data determinatordetermines the acquiring method based upon the computed estimatedpositioning time.
 13. The system of claim 10, wherein the aiding datadeterminator determines the acquiring method based on at least oneparameter selected from a group comprising: a communication state of thecommunications network between the GPS terminal and the location aidingserver, a communications cost, and a user request, wherein the userrequest is at least one request selected from a group comprising:positioning accuracy, positioning time, positioning costs, andpositioning sensitivity.
 14. The system of claim 13, wherein thecommunication state of the network is is determined by at least oneparameter selected from a group comprising an availability of acommunication link to the location aiding server, an effective datatransmission rate of the network and a communication delaycharacteristic of the network,
 15. The system of claim 10, wherein theGPS term nal further comprises a terminal destination calculator forselecting a destination for the GPS terminal and for sending a terminalcalculated position of the GPS terminal, and wherein the location aidingserver further comprises a server destination calculator for selecting adestination for the GPS terminal and for sending a server calculatedposition of the GPS terminal.
 16. The system of claim 15, wherein atleast one of the server calculated position and the terminal calculatedposition of the GPS terminal is shared between the GPS terminal and thelocation aiding server.
 17. The system of claim 10, wherein the aidingdata being sent from the aiding data determinator to the GPS section isdynamically altered based on a change in the state of the GPS section.18. The system of claim 1, wherein the GPS section and the strategyselector pass information between the GPS section and the strategyselector.
 19. The system of claim 18, wherein the information isselected from a group comprising real time data of the GPS section and aquality of service message.
 20. The system of claim 19, wherein thequality of service message is at least one message selected from a groupcomprising: a request or estimated positioning accuracy, a request orestimated positioning time, a request or estimated positioningsensitivity, or information for the necessity of aiding data, and apreferred mode of operation.
 21. A GPS terminal comprising: a GPSsection for receiving and processing a GPS signal; a strategy selector,external to and coupled to the GPS section, that determines apositioning strategy based upon a state of the GPS section.2